Problems
1. (10 pts)
a) How many lines per millimetre would be required in order for the first-order diffraction line for Ã€ = 500 nm to be observed at a reflection angle of -40 degrees (from the surface normal) when the angle of incidence is 60 degrees for a diffraction grating?
b) Considering an infrared grating with 72.0 lines per millimetre and 10.0nm of the illuminated area. Calculate the first-order resolution of this grating. How far
apart (cm must two lines centred at 1000 cm- be if they are to be resolved. 2,
(10 pts) In FI-IR spectrometry, what is the most important physical property of the spectrometer limiting the resolution? What is the expression for resolution in terms of this physical parameter? How do you correct this physical limitation?
3. (20 pts)
a) Draw an energy level diagram describing a Raman scattering process, labelling the Stokes, Anti-Strokes, and Rayleigh lines.
b) Given the relative intensity of the Stokes and Anti-Stokes lines for CCI4 of 56.7 and 12.65 respectively at 2014 cmÂ³ what is the temperature of the sample?
c) At what wavelengths would you measure the Stokes and Anti-Stokes lines if you used a Nd:YAG laser 532 nm to excite the sample?
d) Describe in detail two features which distinguish fluorescence from Raman scattering.
4. (20 pts) A limitation on how many spectra per second can be recorded by a time-of-flight mass spectrometer is the time it takes the slowest ions to go from the source to the detector. Suppose we want to scan up to m/z 500. Calculate the speed of this heaviest ion if it is accelerated through 5.00 kV in the source. How long would it take to drift 2.00 m through a spectrometer? At what frequency could you record spectra if a new extraction cycle were begun each time this heaviest ion reached the detector?
What would be the frequency if you wanted to scan up to m/z 1000?
5. (30 pts) If you design a linear TOF mass spectrometer equipped with a three-electrode, two-stage ion source of / = 30 mm, XA1= 20 mm, XAZ = 30 mm.
a) What value of Xsp should be used in order to achieve 2nd order space focus for ions?
b) Using your derived XSF, and acceleration voltages V1 = 450 V and V2 = 900 Y calculate tTOF for the ions initially located at XA1= 15, 17.5, 20, 22.5 and 25 mm, respectively?
c) Estimate the mass resolution of this linear TOF based on the above results.
6. (10pts) Discuss why it is much easier to couple a gas chromatograph with a mass spectrometer than it is to couple a liquid chromatography with a mass spectrometer.

Problems 1. (10 pts) a) How many lines per millimetre would be re...